Once you get used to turning everything into a metric, it's sometimes hard to turn that part of your brain off. Thus, when you're sitting, watching a fountain in the evening with your wife, after a rare dinner out, you may find yourself inclined to calculate that it just took you an hour and a half to eat a meal that cost you the amount you would make in three hours. And then wonder how many other similar meals your server would have been serving simultaneously, and thus whether if the other couples being served tipped at the same rate the server could have managed to equal your per-hour rate of pay by means of tips.
If you're not a rather hopeless sort of fellow, you don't share these meditations at the time, but in this particular case I found myself wondering the following as well: How does the percentage of income spent on food by modern US citizens compare with most skilled workers throughout history?
In the Pater Noster the only earthy petition mentioned is "give us this day our daily bread" (though as some have pointed out, this can be taken and primarily a Eucharistic reference, and thus not a strictly earthly need). Now, I suspect that for the average household in the modern US, our "daily bread" makes up no more than 10-20% of our household expenses. Why not "give us this day a roof over our heads" or "give us this day a mode of conveyance" or "give us this day affordable insurance"?
Well first of all, food is very basic. One can live without a fixed place of residence or a car (or camel), and it's been pointed out that food will get you through times without insurance better than insurance will get you through times without food.
But it strikes me that this is not just a "back to basics" petition. I'm suspecting that for a basic worker in the ancient world (indeed, perhaps in any primarily agricultural world), food was the largest regular expense. Your earnings might only very slightly exceed the price of obtaining or producing your food for the day.
What, after all, was the cost of clothing? Well, at a basic level, the cost of feeding someone during the period it time it took that person to make them.
The cost of a house? Feeding the workers it took to build a house. I suspect that in a fairly static, agricultural society, there was very little market for selling a house, so the value of a house would be pretty much equal to the materials and labor in building it.
Now clearly, there's more to it than that. People did more than just eat, but not necessarily huge amounts more (in terms of expense) at the lower levels of society -- which meant most of it. I should hunt around a bit and see if I can find some economics work on the question of food as a percentage of personal/family economy in agricultural societies. I could be wrong, but I'm suspecting that the distinction between "poor" and "well off" was very clearly linked to the amount of resources you controlled beyond that necessary just to feed yourself -- and that the values of things were fairly closely tied to the cost of providing food to the workers necessary to produce them.